Interesting...

I think I have a good starting point.

Kolya was very young when he died from the cocaine overdose.

A child dying from cocaine is certainly problematic.

This child's death will impact his parents the most.

Let me investigate his parents.

The database is telling me that Kolya's mother died when he was young.

Kolya had a single father for most of his life.

Kolya's father, Anatoly, is a high-paid doctor.

A high-paid doctor... working long hours... with no family.

Anatoly was never a killer, he was a doctor. He helped people live.

So, if he did kill, this explains the lack of brutality and the precise needle injection.

Anatoly is quite intelligent... His methods were well-thought-out.

He wanted revenge, he wanted to kill people who supply cocaine, because that's how his son died.

I feel... alive... I can use my brain for the greater good.

Forensics... justice... revenge.